At least three Pakistan Army personnel were killed in an exchange of fire with militants in Pakistan's restive Khyber-Pakhtunkhwa province, a military statement said.

The exchange of fire took place in the Kurram district of the province, which also led to the killing of two terrorists, Pakistan military's media wing, the Inter-Services Public Relations (ISPR), said.

The soldiers were identified as Subedar Shuja Muhammad (43), Khuzdar Naik Muhammad Ramzan (32) and Sukkur Sepoy Abdul Rehman (30), it said.

The exchange of fire took place when troops raided a hideout in a former militant stronghold near the Afghan border, the statement said, adding that the raid was carried out to eliminate terrorists from the area.

"Pakistan Army is determined to eliminate the menace of terrorism and such sacrifices of our brave soldiers further strengthen our resolve," the statement said.

The incident came amid a spike in terrorist attacks across the country claimed mostly by the banned Tehreek-e-Taliban Pakistan (TTP) which unilaterally scrapped a ceasefire in November, effectively ending a start-stop negotiation process brokered by the Afghan Taliban, the Express Tribune newspaper reported.

The TTP, which was comprehensively defeated in a decisive kinetic operation by the military, has found safe havens across the border in Afghanistan from where the group has been directing its terrorist operations in Pakistan, the report added.

Last week, a Pakistani Taliban fighter detonated a car bomb in Islamabad and he was from Kurram.

The attack was claimed by TTP, which has reactivated after the capture of Kabul by the Afghan Taliban.

The TTP, believed to be close to al-Qaeda, has been blamed for several deadly attacks across Pakistan, including an attack on army headquarters in 2009, assaults on military bases, and the 2008 bombing of the Marriott Hotel in Islamabad.

In 2014, the Pakistani Taliban stormed the Army Public School (APS) in the northwestern city of Peshawar, killing at least 150 people, including 131 students.

The Friday attack was the first suicide bombing incident in Islamabad since the 2014 courthouse bombing that killed 10 people.